In a disk drive used as an auxiliary storage unit of an information processing system, any one of various disk-shaped storage media (referred to as the storage disk in this specification) such as a magnetic disk, an optical disk and a magneto-optic disk is rotated at high speed, while a head section is caused to perform the tracking operation following a multiplicity of recording tracks formed concentrically on the recording surface of the recording disk thereby to read and write data. The tracking performance of the head section depends on the positioning accuracy in the servo control operation of an actuator supporting the head section. Especially in recent years, with the remarkable increase in the recording density of the storage disk, demand has become increasingly high for a positioning accuracy of the actuator.
For the actuator to perform the highly accurate tracking operation, the external disturbances affecting the operation of the actuator are required to be minimized while at the same time eliminating the vibration of the storage disk as far as possible during rotation. For example, the airflow generated around the storage disk in high-speed rotation becomes turbulent by bombarding the inner wall surface of the casing of the disk drive and may cause the vibration of the actuator and the storage disk. The vibration of the actuator and the storage disk is a factor adversely affecting the head positioning accuracy and the dimensional accuracy of the gap between the head and the recording surface of the disk.
To cope with the vibration due to the airflow, various disk drives have been proposed which include an airflow adjusting mechanism for adjusting the airflow generated around the storage disk rotating at high speed. Japanese Unexamined Patent Publication (Kokai) No. 2000-348465, for example, discloses a hard disk drive having a rectification plate mounted on the inner wall surface of the casing. The rectification plate is a rigid member having the shape of a truncated cylinder partially surrounding the outer peripheral surface of the storage disk, and fixedly fitted in the cylindrical inner wall surface of the casing. The rectification plate is made of a tubular metal material, and has an inner peripheral surface in opposed relation to the storage disk, machined to form a rectification groove extending along the periphery thereof. The rectification plate smoothly guides along the rectification groove the airflow generated around the storage disk rotating at high speed thereby to reduce the effect that the vibration, etc. caused by the airflow has on the storage disk.
Also, Japanese Unexamined Patent Publication (Kokai) No. 2000-357385 discloses a CD-ROM device comprising a plurality of annular grooves formed concentrically of the rotational axis of the disk at locations in opposed relation to the recording surface of the storage disk. These annular grooves guide, in a circular route, the airflow caused by the rotation of the storage disk thereby to alleviate the effect that the vibration or the like caused by the airflow has on the storage disk.
Japanese Unexamined Patent Publication (Kokai) No. 11-297037 discloses a hard disk drive comprising a guide groove for forcibly moving the airflow caused by the rotation of a plurality of storage disks, diametrically outward of the rotation center in the space between the storage disks. This forcible movement of the airflow contributes to the suppression of the vibration of the storage disks.
Japanese Unexamined Patent Publication (Kokai) No. 11-73756 discloses a hard disk drive comprising a plurality of rectification walls for rectifying the airflow caused by the rotation of the storage disk, which rectification walls are formed at the corners inside the casing. The rectification walls form a cylindrical enclosure wall in collaboration with each surface opposed to the storage disk and guide the airflow smoothly.
The specification of U.S. Pat. No. 4,885,652 and Japanese Unexamined Utility Model Publication (Kokai) No. 2-16474 corresponding thereto as well as the specification of U.S. Pat. No. 4,339,777 disclose a disk drive comprising an airflow guide structure for forcibly moving the airflow caused by the rotation of the storage disk, toward an air filter arranged in the casing.
In the prior art, the casing of the disk drive includes a rigid structure made of an ordinary metal material through a casting process and has a bottomed recess for stably accommodating the main essential parts of the disk drive. The conventional various airflow adjusting mechanisms described above, therefore, require some machining step for mounting an independent member such as a rectification plate or a rectification wall on the inner wall surface defining the recess of the casing. This machining process may complicate the production process or increase the production cost of the disk drive.
The object of the present invention is to provide a disk drive for writing and reading data into and from a storage disk, comprising an inexpensive and an easy-to-mount airflow adjusting mechanism for adjusting the airflow generated around the storage disk rotating at high speed thereby to effectively suppress the effect that the vibration or the like caused by the airflow has on the storage disk.
Another object of the invention is to provide a thin-plate member capable of being incorporated, as an airflow adjusting mechanism, in a disk drive.